1. Field of the Invention
The present invention relates to optical disc recording and reproducing technology, and more particularly, to a method of verifying the defect management area information of a recordable and reproducible optical disc.
2. Description of the Related Art
Digital versatile disc-random access memory (DVD-RAM) discs have a defect management function of replacing defective areas with normal recordable areas, and storing information necessary for management of the defective areas in a portion referred to as a defect management area (DMA) thereon. The DMA is repeatedly recorded in four portions on a disc: two portions in a lead-in area and two portions in a lead-out area. DMA information includes a disc definition structure (DDS), a primary defect list (PDL) and a secondary defect list (SDL).
The DMA information includes information on a spare area and important information on the start logical sector number of each zone, in addition to information on defects, which are detected during certification performed while a disc is being initialized or during use of the disc.
Some information included in the DMA can be immediately read and used. On the other hand, the DMA includes information which varies with the positions and the number of defects on a disc. That is, some information, for example, the position information of the start logical sector number of each zone or the position information of a first logical sector number, can be obtained only by performing complex computation according to a given algorithm based on defect information registered in the DMA.
Since such DMA information is closely related to a physical data recording position, a recording medium such as an optical disc, which can be used in a given recording and reproducing apparatus even if the DMA information on the disc has been generated or updated in another recording and reproducing apparatus, may not be compatible with both recording and reproducing apparatuses when the DMA information is wrong. To overcome this problem, a means or method of verifying that a recording and reproducing apparatus correctly reads DMA information from a disc and correctly records DMA information on the disc is desired.